This is difficult to answer, because what works for one person, may not work for the next person. Maybe my answer is a little too "spiritual", but for me it worked on a really practical level: Zazen (Zen meditation).
It's really very simple: you just sit in one of the prescribed positions, inhale through your nose and think of nothing. When you exhale, you count and repeat this process until you've reached ten. So the first breath cycle you count "OOONE" during your exhalation, the second cycle "TWOOO", until you reached ten. Then you start all over again. A more extensive instruction can be found
here.
the non-thinking part during inhalation really is a paradoxical intent, because human beings are unable not to think of anything. What instead will happen, is that all obsetting things that occupy your mind, things you didn't process very well and are stuck in your RAM rather than written away to your your harddisk, will spontaneously pop up. These are thought bubbles. When they appear, you should try not to suppress them nor cling to them, but just observe. Allow them to pop up and allow them to fall again. Just let it happen and observe. After about six weeks of practice (twenty minutes in the morning and twenty minutes at night), the thought bubbles that initially were huge, will become smaller and smaller, until they have become very small dots. You will have processed these experiences and you will find out that they aren't as obsetting as they used to be. They become less and less significant.
I started this practice after I had a heart attack last April. That heart attack was a direct result of me being obset about a lot of things in my life: my gender, abandonment, violence I experienced, a ->-bleeped-<-load of crap. I tried to heal myself afterwards in any way I could and found out that scientific research performed by the American Heart Association has proven that meditation can
reduce the chance of getting another heart attack with 50%. You have to give it some time though, it's not like you've accomplished results after just one meditation session.
The things that occupied my mind don't obset me like they used to and that really is the result of meditation.
I hope that helps.